Vacuum switch



Sept. 29, 1953 F. w. HoTTr-:NROTH 2,653,629

VACUUM SWITCH Filed oct. 3o, 194e Frederid( M Hottenmth WYE/fm PatentedSept. 29, 1953 UNITED STATES PATENT OFFICE VACUUM SWITCH ApplicationOctober 30, 1948, Serial No. 57,480

3 Claims. 1

This invention relates to a vacuum switch and particularly a diaphragmor bellows construction to be used in connection with a control switch,control valve or the like.

One object of the invention is to eliminate the necessity of having arelatively large diaphragm and a relatively large compression springacting against it in order for the diaphragm to respond in a sensitivemanner to pressure less than atmospheric.

Another object is to provide a diaphragm construction that can bereadily mounted on a regulation pressure control switch in place of theusual pressure diaphragm and thus convert the pressure switch into avacuum switch without the necessity of revising the switch action.

More particularly, it is my object to provide a vacuum responsive unithaving a pair of diaphragms of different areas or equivalent means suchas a pair of bellows, the vacuum connection being made to the spacebetween the diaphragms.

A further object is to provide a diaphragm unit for response to vacuumin which the housing for the unit may be secured to a regulationpressure control switch or the like with connection to the space betweenthe diaphragrns of the unit made at the outer end of the unit in thesame position as the usual connection to a pressure diaphragm unit.

With these and other objects in View, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated in theaccompanying drawings, wherein:

Figure l is a vertical sectional view through a vacuum switch embodyingmy invention and showing the parts in the switch-closed position as aresult of a decrease in vacuum or increase in pressure, and

Figure 2 is a view of part '01" Figure l showing the switch in the openposition as a result of an increase in vacuum or decrease in pressure.

On the accompanying drawing I have used the reference numeral IE toindicate a control switch housing having a cover ifi. rThe usualpressure operated control switch mechanism of the character shown in thecopending application of Rothwell and Strasser, Serial No. 71,196, nledJanuary 15, 1949, now Patent No. 2,562,437, issued July 3l, 1951, iscontained in the housing I-IZ and comprises in general the followingdescribed mechanism.

A bracket I4 supports a knife edge pivot rod I6 against which a switchactuating lever I8 is engaged by a range spring 2i! adjustable by meansof a screw 22. The switch arm IS carries a stud 24 for actuating aswitch comprising an actuating spring blade 2B bent to normally assumethe position of Figure l, and stationary and movable contacts 28 and 3.

The contact S is carried by a leaf spring blade 32 which is actuated bya blade 34 pivoted at one end to a bracket 35 and extending through anopening in an extension 3S of the switch blade 32. A spring extendedtoggle link 453 connects the blade 34 with a pointed element 42 on theactuating blade 25.

A diierential widening spring 44 is mounted on a screw 45 on the lowerend of which a nut 48 is mounted. The nut 48 has an extension 5l!traveling in a slot 52 of a bracket 54 to prevent the nut from rotatingwhen the screw 45 is adjusted for varying the tension of the spring 44.

An actuating pin 56 is slidable in a boss 53 of the housing and has ahead 6i! on its lower end. When the foregoing described switch mechanismis operated as a pressure switch, a diaphragm housing is secured to thehousing l@ as shown in the copending application above referred to andhas a pressure responsive diaphragm engaging the head 6U. The pressureresponsive switch may be converted to a vacuum responsive switch bymeans of my present invention comprising a diaphragm unit which will nowbe described, my unit being shown in heavy lines to distinguish it fromthe pressure switch mechanism thus far described.

I provide a diaphragm housing consisting of upper and lower formedplates 52 and secured together by screws Bit with a relatively largediaphragm 68 between them. This diaphragm separates the housing ft2-'S4into two compartments designated lo and l2, respectively.

The plate 32 is secured to the housing i6 by means of screws 'i4 with arelatively small diameter diaphragm 'it interposed between the two. Thisseals on" the compartment "it from atmosphere, whereas uhe compartment'i2 is open to atmosphere by means of a vent opening 13.

Between the diaphragms 53 and lli, I provide a formed spacer plate gli.rIhe compartment lil is the one in my diaphragm unit to be maderesponsive to vacuum and any type of connection may be made to thisspace but preferably I provide a ntting 82 mounted on the outer end ofthe diaphragm housing and connected with the space 'lll by a tube 84.The fitting is thus mounted in the usual position on the diaphragmhousing so as to provide uniformity of installation for the vacuumswitch the same as for the regulation pressure switch.

Practical operation In the operation of my vacuum control device, whenthe pressure is atmospheric or at least less than the desired vacuum atwhich cut out of the switch occurs, the range spring 20 will depress thediaphragms 68 and 76 as illustrated in Figure l thus permitting thespring blade 26 to close the switch contacts 2S and 30.

From the operation just described it is obvious l' that the switch isnormally closed. The switch contacts may be connectedv with, a motorthat operates a vacuum pump or "the likeva'nd they pump may evacuate atank or other receptacle, the tank being hydraulically connectedwith thefitting 82 so that the diaphragm assembly responds to the vacuum createdtherein.' If this vacuum increases (or the pressure decreases .from

atmospheric) there will be an upward movement ofV the large diaphragm 68in proportion tothe difference between its area and the Yarea of thediaphragm l5, the top of whichvis responsive to atmospheric pressure,and the bottomVo-f the dia`v phragm 68 being likewise responsive to atmospheric pressure. ,Y

When the vacuum reaches the desired pressure level for stopping themotor of the vacuum pump it will have raised the diaphragm 63 andsubsequently the spacer Sil and the actuating pin 56 to swing the switchactuating arm IS as tothe 30 to the upper diaphragm which in turn movesvthe actuating pin 5t for performing a control function such as operatingthe switch disclosed or avalve or any other control or indicatingdev1ce.

The diaphragm assembly is so designed as vto respond to maximum vacuumwithout the necessity of providing the usual oversize single vacuumresponsive diaphragm together with the necessary heavy range spring. Myvacuum responsive'diaphragm unit can accordingly be substituted for a,pressure diaphragm unit on a regulation 'pres-` sure actuated controlswitch or valve without having to make any changes such as providing aheavier spring and reversing the switch action or valve action. From amanufacturing standpoint this is a substantial advantage and representsa considerable saving in manufacturing costs.V

While I have shown and described diaphragms 68 and '16, obviously a pairof bellows or equivalent means oan be used and the diaphragms mayoperate any type of control or indicating device without departing fromthe real spirit and purpose of my invention. It is, therefore, myintention to cover by my claims any modified forms of Ystructure or useof mechanical equivalents which mayv be reasonably included within theirscope.

I claim as my invention: 1. In a vacuum actuated control device, adiaphragm housing having an opening, a large diaphragm mounted thereinand separating said diaphragm housing into two chambers sealed by thediaphragm relative to each other, a small diaphragm mounted in lsaidopening and in sealing relation to the wall of said housing surroundingsaid opening, a vacuum connection to the space between said diaphragms,the small diaphragm being adapted to actuate a control element andresponsiveon its outside surface to atmospheric pressure, saidlargerdiaphragm being responsive on its, outside surface to atmosphericpressure, and a spacer between said diaphragms comprising a disc againstsaid large ydiaphragm and slightly smaller than it, said disc having acentrol embossed portion engaging saidsmall dia--v phragm and slightlysmaller than it.

2. In a control device of the character disclosed, a diaphragm housing,large and small diaphragms mounted therein, the small diaphragmV beingadapted for its outer surfaceto actuate a control element and responsiveon the outside to atmospheric pressure, said large diaphragm beingresponsive on its outside tovatmospheric pressure, a spacer between saiddiaphragme, Yand* means for providing a vacuum'connection to the spacebetween said diaphragms comprising a fitting mounted on the outersurface of said diaphragm housing opposite said Aouter surface oi saidsmall diaphragm, and a hydraulic connection between said tting and saidchamber.V f

3. `In a vacuum unit for connection toa control switch or the like, asmall'diaphragm, a large diaphragm spaced therefrom, means forconnecting the peripheries of said diaphragms to form a chamber betweenthem, said small diaphragm being adapted to contact an actuating elementfor said control switch, a spacer between said diaphragms, a cover forsaid large diaphragm,` said cover and said means being connectedtogether, said' cover having an opening to atmosphere, a'

tting mounted on said cover, anda hydraulic connection between saidfitting and said chamber. n 'Y FREDERICK W. Ho-TTENROTH.'

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,510,475 Guenther Oct.,'7, 1924 2,421,284 Peterson May 27,1947 2,435,716

Kearney Feb. l0, 1948

